image credit

Chartered Institution of Water and
Environmental Management (CIWEM)

106-109 Saffron Hill, London, EC1N 8QS  
Tel: 020 7831 3110   Fax: 020 7405 4967

Water Reuse

These pages are intended to provide an overview of water reuse and other alternative water supplies associated with sustainable water management. Each of the seven sub-sections focuses on a different topic and contains background information, illustrated case studies and references. Since this is a web-based resource most of the references are to other internet sources. The case studies cover the full breadth of water reuse applications, from the reuse of municipal wastewater for industry and irrigation of a championship golf course to an urban greywater recycling scheme for blocks of flats.

Click on the sub-section links at the bottom of this page to access the different topics

What is water reuse?

watercycleveoliawater_smallversion.jpgWater reuse describes the process whereby wastewater treated to an appropriate standard, is reused for a variety of beneficial purposes. The treated water ready to be reused is termed recycled or reclaimed water.

There are over 3300 reuse projects internationally with approximately 700 in Europe. The growth in the flow rate capacity each year is 25 to 60% in the countries that recognise the benefits of reuse. Click on the diagram to see an enlarged version of the reuse water cycle .

Why reuse water?

Water is an increasingly scarce resource for much of the World's population. Global warming, an increasing world population and generally increasing incomes mean the demand for water is likely to rise further. If current trends continue, we will use 40% more water by 2024 than we do now. In industrialised countries much of the water used for non-potable purposes such as industrial applications, toilet flushing and irrigation, is unnecessarily treated to potable-water standard. We have to carefully treat wastewater to protect water resources and ensure water is available for abstraction. We need to take care not to over-abstract water from rivers and aquifers but  instead to reduce abstraction to within sustainable limits.

Benefits of water reuse include:

  • Increasing water resource availability
  • Making scarce potable water previously used for non potable applications available for drinking
  • Reduced consumption of expensively treated potable water supplies (cost saving where there is water metering)
  • Reduced effluent flow loads to sewers
  • Reduced nutrient discharge to water bodies
  • Flood prevention potential (storage)
  • A less drought sensitive water resource
  • Enhanced recreation and tourism opportunities and biodiversity benefits through the restoration/creation of wetlands

Is water reuse the only option?

Sustainable water management involves demand-side measures (such as installing water-efficient appliances, bathroom fittings and being 'waterwise') as well as the supply-side measures which are discussed in this section (water reuse other and other alternative water supplies like appropriately treated rainwater and desalinised sea water). Usually it is more effective to reduce demand for water at point of use before supply-side measures are initiated.


 Further information:


Upcoming Events


Page Documents x


Chartered Institution of Water and
Environmental Management (CIWEM)

106-109 Saffron Hill, London, EC1N 8QS  
Tel: 020 7831 3110   Fax: 020 7405 4967